I am getting the following error when trying to preview the report:
Table (id = 128):
+ Column binding "WTSK_TME_CMPLTD" has referred to a data set column "WTSK_TME_CMPLTD" which does not exist. (Element ID:128)
data.engine.ColumnBindingReferToInexistColumn ( 1 time(s) )
detail : org.eclipse.birt.report.engine.api.EngineException: Column binding "WTSK_TME_CMPLTD" has referred to a data set column "WTSK_TME_CMPLTD" which does not exist. (Element ID:128)
at org.eclipse.birt.report.engine.executor.ExecutionContext.addException(ExecutionContext.java:1237)

It doesn't like DATE(F.WTSK_TME_CMPLTD) CS_SMRY_CMPLTD_DTE. CS_SMRY_CMPLTD_DTE is being displayed as a column under the data set. I dragged CS_SMRY_CMPLTD_DTE to my table column and tried to preview it.